<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <!-- <script src="vue.js" type="text/javascript" charset="utf-8"></script> -->
    <script src="https://cdn.jsdelivr.net/npm/vue/dist/vue.js"></script>
    <script src="https://unpkg.com/axios/dist/axios.min.js"></script>
</head>
<body>
    <div id="app">
       <input type="button" value="获取笑话" @click="getJoke">
       <p>{{joke}}</p>
    </div>
    <script> 
        // axios回调函数中的this已经改变，无法访问到data中数据
        // 把this保存起来，回调函数中直接使用保存的this即可
        // 和本地应用最大的区别就是改变了数据来源
        var app= new Vue({ 
            el:"#app",
            data:{
                joke:"很好笑的笑话"
            },
            methods: {
              getJoke:function(){
                  //console.log(this.joke);
                  var that = this ;  //因为后边this  会变  所以 提前取走this
                axios.get("https://autumnfish.cn/api/joke")
                .then(function (response) {
                   // console.log(response);
                   // console.log(response.data);
                   // console.log(this.joke); //此时this 已经变了 
                    that.joke = response.data;
                })
                .catch(function (error) {
                })
              }
            }, 
        });

    </script>
</body>
</html>